Hydraulic rotary drill



June 16, 1936. w. L. DIEHL 2,044,349

HYDRAULIC ROTARY DRILL I Filed Feb. 16, 1952 4 Sheet-Sheet 1 gwnliovJune 16, w DIEHL HYDRAULIC ROTARY DRILL Filed Feb. 16, 1932 4Sheets-Sheet 2 :gwx am Huunu June 16, 1936. w LY DlEHL 2,044,349

HYDRAULIC ROTARY DRILL Filed Feb. 16, 1932 4 Sheets-Sheet 3 NITED STATESPATENT OFFICE HYDRAULIC ROTARY DRILL Webster L. Diehl, St. Joseph, Mo.

Application February 16, 1932, Serial No. 593,277

Claims.

This invention relates to well drilling apparatus.

Specifically referred to herein will be that type of well drillingapparatus which, practically continuously during operation, is madeeffective by means of a drill-point deriving its power from afluid-operated turbine. This turbine, in one form of the invention, iscarried within a long shaft, extending down into the ground. In apreferred case, the shaft, as it moves into the well being prepared forit by the drill-point, is itself rotated by power means independent ofthe turbine.

The factor of the great mass of shafts such as these, which aregenerally of great length, and the large amount of power necessarilyused in effecting their rotation, is probably the most vital one inmaking desirable the operation of the drill-point by independent powermeans. Since some fluid, such as water, is customarily forced down theshaft to discharge around the drillpoint, acting as a lubricant infacilitating the drill operation and carrying away dbris formed as thedrill-point is active, the hydraulic pressure of this fluid may be madeto actuate the turbine and rotate the point. However, during theoperation of these drill-points, it occasionally happens that the powerdeveloped by the turbine is insuificient to overcome the resistance ofsome obstruction of greater impenetrability than the ground throughwhich the drill-point is moving. In such case, in spite of continuedflow of fluid through the turbine, rotation of the drill-point willcease and the apparatus would become ineffective. Even continuedrotation of the shaft itself from its independent power means would beineffective to rotate the drill.

It is an object of the invention to provide means for coupling thedrill-point directly to the shaft on such occasions when the drill-pointdoes not derive sufficient power from the fluid to overcome suchincreased resistance. For this purpose, between the shaft and thedrill-point, there may be provided a coiled member having an end affixedto one of them. The other end of the member is provided with meanscooperating with a complementary portion on the part to which it is notsecured so that the shaft and the point may unhindered rotate relativelyin one direction; upon commencement of relative rotation in the oppositedirection, interlocking of the end of the member and the cooperatingportion will ensue.

Rotation of the drill-point, when driven by the turbine, is generally ata higher rate than that of the shaft so that normally the drill-pointand the shaft will rotate relatively in one direction. Should theturbines power become insufiicient, or the drill-point be stoppedagainst an obstruction, or its rotation cease for any other reason, andif the shaft continue. rotating, the direction of relative rotation ofdrill-point and shaft will be reversed, and immediately there willresult an interlock between the free end of the member and thecooperating portion. The coiled member will be forced to expand, and. byits expansion, caused to engage cooperating portions of the shaft andthe drill-point. Expansion of the member will continue until it gripsthese portions so tightly as to form a substantially rigid couplingbetween them, in which case the drill-point will then be drivenpositively from the rotating shaft. After the drill-point has clearedits obstruction, the coiled spring will, by its own elasticity, tend toreturn to its original formation and release the point and the shaft oftheir interengagement, whereupon the turbine will resume driving thedrill-point until the next obstruction is met.

To safeguard the several parts of drilling apparatus, sunk in the welland inaccessible practically at all times after operation commences,lubrication under pressure has become arequisite. It is an object of theinvention to provide, for well drills of this character, a lubricationsystem in which the fluid under pressure, necessary for turbineoperation and for dbris elimination, is made the active agent inmaintaining lubricant at the several parts under pressure greater thanthat of any neighboring fluid source. The resultant pressure of thelubricant at operating parts located beyond the turbine, is much higherthan the fluid pressure at this location, since the pressure head lossin the turbine reduced it much below the original fluid pressure, andthe pressure of the lubricant. Infiltration of water into the lubricantis thus substantially eliminated, as the tendency, in such case, is thatlubricant pass out of the lubricated parts.

It is an object of the invention to provide a system of gearing by whichthe relatively slow speed drill-point may be driven by the customaryhigh minimum speed turbine. In one case, the principle of the epicyclicgear train is used, while in another case, an annular gear is driven bya pinion on the turbine shaft. In the form using the epicyclic train,the annular gear is preferably stationary with the drill shaft, whilethe p anetary gears are affixed in a member coupled to the drill-point.It is also desired that such system of gearing be arranged to permitreadily interchanging sets of gears for obtaining different ratios ofreduction.

While a high degree of reduction may be effected in the system using anannular gear, driven by a pinion gear on the turbine shaft, it is,however, desirable to reduce the turbine speed as much as possiblewithout affecting the power derived. For this purpose, the turbine maybe built in a substantially large number of stages so that the pressuredrop in each stage will be decreased, whilethe effective power deliveredwill be the same.

In normal operation, the drill-point, driven by the turbine, shouldrotate at a speed greater than that of the drill shaft. It is desirablethat the operator may determine if and when the drill .is being drivenby the shaft itself for any continuous period, so that he may remedyimmediately any emergency that may have arisen. With the drill and theturbine entirely incased and within the ground, direct observation isnot practical. It is an iectnfiheiarenii nialt dewh'erebyianoperatonmay.determineQatiany "life during drillin..thmrelmiras ead Of rill-point and dfill shaft. thisiiui poseftlfere ismounted upon the turbine shaft, a spring member which, by contacting astationary point on the shaft, may complete a circuit for a gong or likeindicator, externally of the apparatus. e. number of indications for aunit time will irg r ,itriefdpratdrfwfi g drill-point is beingdrivenbywturbineior,shaftl Inthe l'at't'ercase, the gong would not timeat. all.

Other objects of this invention will hereinafter be set forth, or willbe apparent from the description and the drawings, in whichareillustrated embodiments of apparatus for carrying out the invention.

The invention, however, is not intended to be restricted to anyparticular construction or arrangement of parts, orto any particularapplication of such construction, or to any specific manner of use, orto any of the various details thereof, herein shown and described, asthe same may be modified in various particulars or be applied in manyvaried relations without departing from the spirit and scope of theclaimed invention, the practical embodiments herein illustrated anddescribed merely showing some of the various forms and modifications inwhich the invention might be embodied.

On the drawings, in which the same reference characters refer to thesame parts throughout, and in which are disclosed preferred embodiments:

Fig. 1 is an elevational view of the entire drill shaft, illustratingthe arrangement of the drillpoint and associated elements;

Fig. 2 is a View in perspective of the apparatus within the shaft fromthe topmost portion to the gear cut on the shaft and driven by theturbine;

Figs. 3, 4 and 5, in the order named, are sectional views, to anenlarged scale, longitudinally of a drill shaft, parts being shown inelevation, and all taken together showing the shaft as arranged andembodying the invention;

Fig. 6 is a detail sectional view to a still larger scale, parts beingshown in elevation, illustrating the outlet from the lubricantcompression chamber;

Fig. 7 is a transverse sectional view on the line 1-1 of Fig. 4, to thesame scale as Fig. 6;

Fig. 8 is a transverse sectional view on the line 8-8 of Fig. 4, to thesame scale as Fig. 6;

Fig. 9 is a transverse sectional view on the line In one form ofapparatus for 9-9 of Fig. 5, illustrating, to an enlarged scale, thearrangement of the end of the coiled coupling device; and

Fig. 10 is an elevational view, to the same scale as Fig. 9, of partsincluding the'coiled coupling member of the drill-point drive, some ofthe parts being shown in section.

The drill shaft in, here illustrated as embodying the invention,consists of a shell I2 within which preferably are housed all elementsnormally necessary for carrying on drilling. At the top of the shell isgenerally situated an orifice member M, the effective cross-section ofwhich, at point I 6, determines the quantity of fluid flowing downthrough the system.

The shell may be made up of a plurality of separable sections, thetopmost of which may be member l4, threadedly engaged, or in any othersuitable manner retained assembled, to form the shell. Preferably justbeneath member I4 is located a cylinder I8 of uniform bore within whichis reciprocable a piston 20. The topmost portion of cylinder I8 is opento the interior of the shell at this point, a cap 22 having an opening24 permitting limited admission of fluid into the chamber 25 defined bycylinder I8 and piston 20.

The cylinder is engaged by a coupling 28, or in any other manner issecured to a valve housing 30, which may be an integral part of acasting 32. The outer wall 34 of the casting preferably forms acontinuation of shell I2, the housing being spaced away from the wall bymeans of ribs 36 to provide passages 38 for fluid flowing around thehousing. The housing is provided with a passage 49 across which, at anintermediate point, a plug 42 is movable by screwing it in and out of athreaded wall 44. Access to the plug and its lock nut 45 may be hadthrough an opening 45 in wall 34, which is normally closed by a plug 50.Adjustment of plug 62 results in a variance of the effectivecross-section of passage 40, and, therefore, in control of the amount oflubricant passing down through the passage.

Housing 35 may also provide an upper bearing for turbine shaft 52 overwhich is received a sleeve 55. To provide against leakage of lubricantbetween shaft and sleeve, rings 56 are disposed upon the shaft. Thelubricant passes from passage 58, entering at the upper end of the shafta passage 58 through the shaft. Roller bearings 65 may be carried. by asuitable race for reducing friction between housing 35 and the sleevewhen the shaft rotates. The seal formed by spring-pressed washers 52 andpacking 64, forced tightly around the shaft by means of a compresser 65engaged against the end of the housing by suitable means, preventspassage of lubricant into the shell of the drill shaft.

The passage 58, formed through the shaft, extends down into housing 68and into the chamber 75 in which it discharges. Preferably immediatelybelow housing 36, shaft 52 has mounted upon it, in any desired manner,the vanes 12 of turbine 14 so located as to cooperate with stationaryvanes 16, formed with, or otherwise secured to, a sleeve '18 forming apart of shell l2. Preferably, the vanes are arranged in a plurality ofsuccessive stages, the number of stages being such that the effectivespeed of the rotating shaft will be low, the drop in pressure betweenstages being sufficiently reduced for this purpose, whereas, bydisposing a suflicient number of stages, practically the entire powerderivable from fluid under pressure will be transmitted by the turbineto shaft 52.

Beyond the turbine, the shaft enters housing 68. The upper end of thehousing is protected against inflow of fluid by means of a stufling box80 and the spring-pressed seal 82. The housing is supported from asleeve 84 by ribs 86, thus leaving passages 88 around the housing forfluid flow. A shoulder 90 internally of the housing provides support fora ball race 92, which forms a bearing for the turbine shaft. Adjacentits end, the shaft has a gear 94 cut in its surface. The lower end ofthe shaft preferably is slightly beveled and rests upon roller bearings96, set slightly at an angle to act as a bottom bearing for the shaft.Forming a part of housing 68 and preferably assembled therewith in anydesired manner is an annulus 98 which, on the same level as gear 94, hascut therein teeth to form an annular internal gear I00. The annulus isbraced away from the shell by means of lugs I02.

Between gears 94 and I are positioned a plurality of pinions I04,meshing with both gears. These pinions are carried by pins I06 betweenwhich and the pinions the roller bearings I08 are assembled. The pinsare supported in a cage IIIJ formed at the upper end of a shaft H2. Thecage has a recess II4 for receiving the end of shaft 52 and rollerbearing 96. Pins I06 have both top and bottom bearings in the cage. Ballraces H6 and H8 permit relative rotation of shaft H2 and annulus 98.

Lubricant entering chamber I0 passes down over ball races 92 and H6,through chamber I20, formed by annulus 98, and sealed off at its lowerend by a stuffing box I22 and spring-pressed members I24. From chamberI20, lubricant passes down through a passage I26, preferably centrallyformed in shaft II2, to discharge into a tube I28, immediately at theend of shaft II2, which tube collects and conducts away the lubricant ashereinafter further indicated.

It will be noted that, as shaft 52 is rotated by the turbine, it drivesthe epicyclic train constituted by gear 94, pinions I04 and gear I00, torotate shaft II2 relatively to the relatively stationary annular gearI00. The degree of reduction will be determined by the proportionalsizes and disposition of the gears.

On shaft H2, immediately below stufiing box I 22, may be secured aspring finger I36 having a contact button I32 at its outer end. Thisbutton is positioned and is intended to. contact wilh a button I34carried by an insulator I36 secured to the shell. A suitably insulatedconductor may pass up through the passages within the shell, or in anyother manner be brought to the surface, where, by means, such as acommutator, the make-and-break action of the two buttons may be used toenergize some suitable appliance (not shown), such as a gong, forindicating the number of times the buttons make contact, whereby it ispossible to determine the relative rotational speed of shaft I I2 andthe shell.

The end of shaft I I2 is splined or otherwise retained against rotationrelative to a tubular shaft I38. Immediately below the beginning ofshaft I38, and tube I 28 and its sealing washer I40, a

passage I42 is provided through the wall of shaft I38 for the entranceof fluid from the drill shell into the duct I44 provided centrally ofshaft I38. This duct extends through the entire length of the shaft downto drill-point I46 at which the fluid discharges, facilitating operationof the point and washing away dbris formed and driving such debrisupwardly away from the drill-point.

guul VII Tube I28 is bent over, as shown at I48, and retained by asuitable finger I50 against the wall of shaft I38, along which itextends to a chamber I52, defined by suitable packing glands at top andbottom of sections I54 and I56, forming part of the shell, and intowhich it empties.

Within the chamber I52 and encircling shaft I38 is a coiled spring I58,the upper end of which terminates in an upright prong I60. An openingI62 is provided in section I56 Within which prong I60 is engaged. Thelower end of the spring may be formed with a sharp pointed tooth I64which, by the pressure of the spring, is forced into engagement with aledge I66 of a shouldered sleeve I68, which is secured to the drill-headsocket I10 by any suitable means. Tooth I64 is intended normally to rideover teeth I12 in the ledge, that is, normally the rotation of the shaftwill be such that sleeve I 68 will slide by the relatively stationaryspring I58. If, however, rotation of the sleeve, which is splined toshaft I30, should no longer be effected by the turbine, and the shell,continuously rotated by suitable power means (not shown), shouldcontinue so to rotate, teeth I64 and H2 will engage. Immediately, aswill be seen from Fig. 10, expansion of coiled spring I58 will occur,until finally the spring will engage against the substantially co-axialand equiradial walls I14 and I76 of section I56 and sleeve I68, thuscoupling these two pieces together and making them as one so that thesection will transmit power to the sleeve as the shell rotates. In otherwords, the drill-point I46 will thus be directly coupled to the shelland be driven thereby. A suitable roller bearing I18 may be positionedbe tween the sleeve and section I56 for Well known purposes.

It is to be noted that, in the case of the gear reduction described, theelements are mounted within separable sections of the shell, permittingready dissociation and assembly, either for replacement or, as here incase of the gears and turbines, to permit variation of the relation ofthe parts to each other, by introducing more stages into the turbine, orby changing the gear relationship.

Many other changes could be effected in the particular apparatusdesigned, and in the methods of operation set forth, and in the specificdetails thereof, without substantially departing from the inventionhereof intended to be defined in the claims, the specific descriptionherein being merely to illustrate operative embodiments carrying out thespirit of the invention.

What is claimed as new and useful is- 1. In well-drilling apparatusincluding a drill casing, means for causing rotation of the casing, adrill-point, means carried by the casing for efiecting rotation of thedrill-point relative to the casing, and resilient means to couple thepoint directly to the casing when the rotation-effecting means isineffective to cause such relative rotation, the coupling actionbecoming more intense with increased transmission of force therethrough.

2. In well-drilling apparatus including a drill casing, means forcausing rotation of the casing, a drill-point, means carried by thecasing for effecting rotation of the drill-point at greater speed thanthe casing, and means to couple the 70 point directly to the casing whenthe rotationefiecting means is inefiective to produce such greaterspeed, the coupling action becoming more intense with increasedtransmission of force therethrough. 7 5

QTI

3; In well-drilling apparatus including a drill casing, means forcausing rotation of the casing, a drill-point, a fluid-actuated motorcarried by the casing for efiectmg rotation of the drill-point relativeto the casing, and means to couple the point directly to the casing whenthe motor is ineffective to cause such relative rotation, the couplingaction becoming more intense with increased transmission of forcetherethrough.

4. In well-drilling apparatus including a drill casing, means forcausing rotation of the casing, a drill-point, means carried by thecasing for effecting rotation of the drill-point relative to the casing,and means for forming an interconnection between the point and thecasing and secured to one of them, said interconnecting means, when therotation-effecting means is ineffective to cause such relative rotationof point and casing, positively engaging the other of them to drive thepoint directly from the rotating casing.

5. In well-drilling apparatus including a drill casing, means forcausing rotation of the casing, a drill-point, means carried by thecasing for effecting rotation of the drill-point relative to the casing,and means for forming an interconnection between the point and thecasing and secured to one of them, said interconnecting means includinga resilient member which, when the rotationefiecting means isineffective to cause such relative rotation of point and casing,positively engages the other of them to drive the point directly fromthe rotating casing.

6. In well-drilling apparatus including a drill casing, means forcausing rotation of the casing, a drill-point, means carried by thecasing for effecting rotation of the drill-point relative to the casing,and means for forming an interconnection between the point and thecasing and secured to one of them, said interconnecting means includinga coiled spring which, when the rotationeffecting means is ineffectiveto cause such relative rotation of point and casing, positively engagesthe other of them to drive the point directly from the rotating casing.

7. In well-drilling apparatus including a drill casing, means forcausing rotation of the casing, a drill-point, means carried by thecasing for efiecting rotation of the drill-point relative to the casing,and means for forming an interconnection between the point and thecasing and secured to one of them, said interconnecting means includinga coiled spring which, when the rotation-effecting means is ineffectiveto cause such relative rotation of point and casing, is uncoiled andpositively engages the other of them to drive the point directly fromthe rotating casing.

8. In well-drilling apparatus including a drill casing, means forcausing rotation of the casing, a drill-point, means carried by thecasing for effecting rotation of the drill-point relative to the casing,and a coiled spring between the point and the casing and secured to oneof them, the other having means for engagement by the spring, saidspring being normally of an efiective diameter less than that of thecasing and of a diameter to maintain it out of engagement with theengagement means, but when the rotation-effecting means is ineffectiveto cause such relative rotation of point and casing, positively engagingthe engagement means to drive the point directly from the rotatingcasing.

9. In well-drilling apparatus, a drill casing carrying a drill-point.and means for rotating the point including a liquid flow actuated devicefor energizing the point, m eans.ior. l ubricating the ggyln cnwmi lthaenaratuslsaidrm ing the liguid atth e p r e ssure before a jlaencaalanauth -H t, d" "fvice', and the liquid from"'tliedvice discharging a SAQRQIH S a MM" mung lubricant.

"TOTIKWell-drilling apparatus including a drill shell, a drill-point,means for rotating the shell, means in the shell for rotating the pointrelatively to the shell, and means for coupling the point to be drivenby the shell when the point rotating means becomes inefiective and meansiglilllifittillgi fl ,n latiitatspeedsmqi. Q2 telllll hdsp 11. Inwell-drilling apparatus including a drill casing, a drill-point, meansfor rotating the casing, an hydraulically operate-d motor assembledwithin the casing for effecting rotation of the point relative to thecasing, and transmission means within the casing and between the pointand the motor; an enclosing chamber for the transmission means; thetransmission means including a member coupled to the point and extendinginto the chamber, a shaft extending from the motor and into the chamber,and gearing between the member and the shaft within the chamber; theliquid discharge from the motor passing down through the casing aroundthe chamber, the chamber being filled with lubricant in which the gearsoperate, and means to maintain the lubricant under pressure to preventleakage of the discharged liquid into the chamber.

12. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, means for retaining adrillp-oint, means for operating the drill-point retaining means, theoperating means being directly coupled to the drill-point retainingmeans, the drill-point retaining means having a wall formed to besubstantially co-extensive with the casing wall, the drill-pointretaining means and the casing normally providing a pair of relativelyrotatable members, a coiled spring, one end of the spring being securedto one of the members, and means on the other member for engaging theother end of the spring to cause it to uncoil into engagement with thewalls when the operating means becomes ineffective, whereby thedrill-point retaining means and the casing will be caused to move as aunit.

13. In well-drilling apparatus, a drill casing,

means for causing rotation of the casing, a drillpoint, means carried bythe casing for rotating the point relatively to the casing, a resilientmember extending between the casing and the point and fixedly engagingone of them, and

means for effecting engagement between the resilient member and theother of them to force the member into coupling relation with casing andpoint and secure direct drive relation between casing and point, theengagement-effecting means becoming operative when relative rotationceases.

14. In well-drilling apparatus, a drill casing, means for causingrotation of the casing, a drillpoint, means carried by the casing forrotating the point relatively to the casing, the casing and point beingformed with adjacent inner walls of substantially the same radius ofcurvature, a resilient member extending between the casing and the pointand fixedly enga ing one of them, the

1,. beinacgndl isd .1 points bflQYUh resilient member normally being outof engagement at least with the wall of the other, and means foreffecting engagement between the resilient member and the wallsto forcethe member into coupling relation with casing and point and securedirect drive relation between casing and point, theengagement-effectingmeans becoming operative when relative rotationceases.

15. In well-drilling apparatus, a drill casing, means for causingrotation of the casing, a drillpoint, means carried by the casing forrotating the point relatively to the casing, the casing and point beingformed with adjacent walls of sub stantially the same radius ofcurvature, a resilient member extending between the casing and the pointand fixedly engaging one of them, a toothed wall on the other, theresilient member normally being out of engagement at least with the wallof the other and having a free end normally moving over the toothedwall, said free end being adapted positively to engage the toothed walland to force the resilient member to engage both walls to force themember into coupling relation with casing and point and secure directdrive relation between casing and point, said free end becomingeffective when relative rotation ceases.

16. In well-drilling apparatus including a drill casing, a drill-point,means forrotating the casing, means assembled with the casing foreffecting rotation of the point relative to the casing, transmissionmeans between the point and its rotating means including a membercoupled to the point and carrying a planetary gear, an annular gearfixedly associated with the casing and engaged by the planetary gear, ashaft extending from the point-rotating means and having a sun gearthereon engaging the planetary gear, the casing and the point beingformed with walls of substantially the same radius of curvature, aresilient member extending between the casing and the point and fixedlyengaging one of them, and a toothed wall on one of them, the resilientmember normally being out of engagement at least with the wall of one ofthem and having a free end normally moving over the toothed wall andadapted to engage a tooth of said toothed wall when relative rotationbetween casing and point ceases, thereby forcing the resilient merriberto engage both walls, whereby the membe is forced into coupling relationwith casing and point and secures direct drive relation between casingand point. I

17. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, said casing having achamber defined therein, a drill-point socket, means within the chamberfor operating the socket, the operating means being directly coupled tothe socket, and resilient means for effecting a coupling directlybetween the socket and the casing when the socket-operating meansbecomes ineffective, whereby the socket and the casing will be caused tomove as a unit.

18. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, a drill-point socket,means for operating the socket, the operating means being directlycoupled to the socket, and resilient means for effecting a couplingdirectly between the socket and a wall of the casing when thesocket-operating means becomes ineffective, whereby the socket and thecasing will be caused to move as a unit.

19. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, a drill-point socket,means for operating the socket, the operating means being directlycoupled to the socket, and

a coiled spring for effecting a coupling directly 5 between the socketand a wall of the casing when k the socket-operating means becomesinefiective, whereby the socket and the casing will be caused to move as.a unit.

20. In a well-drilling system including a cas- 0 ing for movement intothe well as it is drilled, the casing being rotated, a drill-pointsocket, means for operating the socket, the operating means beingdirectly coupled to the socket, the socket having a wall, and a coiledspring for effeet-ing a coupling directly between the walls of thesocket and the casing when the socket-operating means becomesinefiective, whereby the socket and the casing will be caused to move asa unit.

21. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, a drill-point socket,means for operating the socket, the operating means being directlycoupled to the socket, the socket having a wall formed to besubstantially co-extensive with the casing wall, and a coiled spring foreffecting a coupling directly between the walls of the socket and thecasing when the socket-operating means becomes ineffective, whereby thesocket and the casing will be caused to move as a unit.

22-. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, a drill-point socket,means for operating the socket, the operating means being directlycoupled to the socket, the socket having a wall formed to besubstantially co-extensive with the casing wall, and a coiled spring foruncoiling to form a coupling directly between the walls of the socketand the casing when the socket-operating means becomes inefiective,whereby the socket and the casing will be caused to move as .a unit.

23. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, means for retaining adrill-point, means for operating the drill-point retaining means, theoperating means being directly coupled to the drill-point retainingmeans, the drill-point retaining means having a wall, the drill-pointretaining means and the casing normally providing a pair of relativelyrotatable members, a coiled spring, one end of the spring being securedto one of the members, and means on the other member for engaging theother end of the spring to cause the spring to effect a couplingdirectly between the walls of the drill-point retaining means and thecasing when the operating means becomes ineffective, whereby the drill-0 point retaining means and the casing will be caused to move as a unit.

24. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, means for retaining adrillpoint, means for operating the drill-point retaining means, theoperating means being directly coupled to the drill-point retainingmeans, the drill-point retaining means having a wall, the drill-pointretaining means and the casing nor- 7O mally providing a pair ofrelatively rotatable members, a coiled spring, one end of the springbeing secured to one of the members, and a ratchet on the other memberfor engaging the other end of the spring to cause thefspring to effect acoupling directly between the Walls of the drill-point retaining meansand the casing when the operating means becomes inefiective, whereby thedrill-point retaining means and the casing will be caused to move as aunit.

25. In a well-drilling system including a casing for movement into thewell as it is drilled, the casing being rotated, means for retaining adrillpoint, means for operating the drill-point retaining means, theoperating means being directly coupled to the drill-point retainingmeans, the drill-point retaining means having a wall, the

drill-point retaining means and the casing normally providing a pair ofrelatively rotatable members, a coiled spring, one end of the springbeing secured to one of the members, and means on the other member forengaging the other end of the spring to cause it to uncoil intoengagement with the walls of the socket and the casing when theoperating means becomes ineffective, whereby the drill-point retainingmeans and. the casing will be caused to move as a unit.

WEBSTER L. DIEHL.

